1. Field of the Invention
The present invention is directed to the mixed anhydride of acetic and (1R,cis)-caronaldehydic acids, a useful chemical intermediate in a process for the preparation of (1R,cis)-caronaldehydic acid.
2. Description of the Prior Art
U.S. Pat. No. 3,723,469 describes (1R,cis)-caronaldehydic acid (the internal hemiacylal of (1R,cis)-3,3-dimethyl-2-formyl-cyclopropane-1-carboxylic acid) as an intermediate for the preparation of certain 2,2-dimethyl-3-substituted-vinyl-cyclopropane-1-carboxylic acids, the starting material for the preparation of (1R,cis)-caronaldehydic acid being (1R,trans)-chrysanthemic acid.
The present process affords a method for preparing (1R,cis)-caronaldehydic acid ultimately from the very inexpensive, abundant and readily available natural terpene, (+)-.DELTA..sup.3 -carene, using certain new chemical intermediates.